This invention is generally related to closure and discharge devices for the discharge opening of hoppers containing particulate material and more specifically to an air and moisture resistant closure combined with a butterfly valve discharge control device positioned and secured under the discharge opening of a hopper.
The prior discharge devices for hoppers of the type used on semi-trailers, railroad cars or storage bins have been complex in construction and expensive to manufacture. For applications such as on semi-trailers and railroad cars, where the area surrounding the discharge opening is subjected to salt, slush, snow, cinders, dust, oil, dirt and similar contaminating materials, discharge devices have failed to adequately protect particulate material carried in the hopper from contamination both when the hopper is being transported from one location to another and when at a fixed discharge position at which the particulate material is dispensed from the hopper.
Discharge devices in the past which were capable of sealing the discharge opening of a hopper have been of substantial vertical height thereby causing the hopper to be positioned high above the highway or railroad tracks thereby reducing the stability of the semi-trailer or railroad car on which the hopper is mounted.
Accordingly, it is the principal object of this invention to provide a new and improved discharge assembly for preventing the contamination of material in a hopper during rail or other transportation of the hopper and when the hopper is at a discharge location for a dispensing of material from the hopper.
Another object of the present invention is to provide a discharge gate assembly which may be assembled and operated easily and quickly.
An additional object of the present invention is to provide a discharge gate assembly which is simple to manufacture and rugged in construction.
A further object of the present invention is to provide a hopper discharge gate assembly which projects a minimum distance below the discharge opening of the hopper to provide maximum ground clearance when the hopper is mounted on semi-trailers or railroad cars.
Yet another object of the present invention is the provision of an improved hopper discharge gate assembly with a manually operable valve to control the flow of particulate material from the hopper.
Achievement of the objects of this invention is enabled through the provision of a hopper having side walls and a discharge opening and a frame pivoted on a hinge connected to one of the hopper side wall and movable to a position covering the discharge opening. A seal is provided between the frame and the hopper to prevent contamination of the contents of the hopper. A passageway extends through the frame to permit dispensing of particulate material carried in the hopper. Control of the flow of particulate material through the passageway is achieved with a butterfly valve having a disc positioned in the passageway to restrict or prevent the flow of particulate material through the passageway. The butterfly valve disc is rotatable between fully opened and closed positions by a manually operated crank handle connected to the butterfly valve disc. The frame has downwardly and outwardly extending flange members to shield the passageway from contamination. A bottom cover, conforming to the bottom of the frame and the frame flange members, is removably secured over the passageway and against a resilient seal surrounding the passageway to prevent the entry of contaminants into the particulate material being carried in the hopper. The side walls of the hopper and the edges of the discharge opening may be covered with a flexible hopper liner.
The manner in which the preferred embodiment of the invention achieves the objects of the invention will become more apparent when the following written description is considered in conjunction with the accompanying drawings.